Greater Cairo, Egypt, which lies in the apex of the Nile Delta, is one of the most populated regions in the world. Air pollution is a profound environmental issue prevailing in the urban/rural landscapes of this crowded megacity. The objectives of the present study were to utilize remotely sensed data in order to address the seasonal variations of the nocturnal surface urban heat island intensity (SUHII) as extracted from the American Moderate Resolution Imaging Spectroradiometer (MODIS) satellite and the related seasonal distribution of selected air pollutants, including nitrogen dioxide (NO₂), sulphur dioxide (SO₂), and carbon monoxide (CO) as extracted from the European TROPOspheric Monitoring Instrument (TROPOMI) for the period from 2018 to 2021. It is observed that there is clear nocturnal urban heat island over Greater Cairo, particularly at the administrative districts dominated by urban land use with high density of population and at the industrial and power generation locations. The highest SUHII is observed during winter. On the other hand, the selected pollutants also represent an urban pollution island (UPI) capping the regions of high SUHII. At the seasonal level, the highest NO₂ correlation with the SUHII occurs during spring (R² = 0.59), while the CO correlates maximum during winter (R² = 0.51). Nonetheless, the seasonal SO₂ distribution is poorly related to the SUHII as this specific pollutant is significantly associated with the industrial land use. Climatic and topographic factors could intensify the distribution of air pollution in the study area. Results of this study demonstrate the significance of geospatial technology tools in the subtle analysis and addressing regional air pollution. The outputs are also of a paramount implication on the management of urban environment and the adaptation of urban air quality.

The simultaneous biosorption of chromium (VI), copper (II), iron (II), and nickel (II) was investigated by alkaline-modified Chlorella vulgaris and Spirulina platensis in binary systems. The alkaline modified biosorbents were CV-KCl, SP-KCl, CV-Na2CO3, and SP-Na2CO3. The maximum removal efficiency recorded in this study was 99.7% with a biosorbent dosage of 0.3 g within a pH range of 2 to 6. The highest biosorption capacities obtained were 14.1, 13.5, 21.6, and 15.8 mg/g for Cr (VI), Cu (II), Fe (II), and Ni (II), respectively. The pseudo-second-order best described the biosorption rate, while the Langmuir isotherm model best described the biosorption equilibrium interaction. The values for Gibbs free energy (ΔG°) were in the range of 0.5 to 6.5 kJ/mol (Cr-Fe), 1.3 to 8.4 kJ/mol (Cr-Ni), and 3.9 to 11.3 kJ/mol (Cr-Cu) binary systems. This showed that the biosorption processes were characterized by physisorption reactions. The Temkin constant B values were in the range of 0.339 to 1.485 kcal/mol and the biosorption processes were largely exothermic reactions. The values for the Freundlich constant KF were between 1.4 and 10.4 (L/g), which indicated favourable biosorption. The Temkin isotherm model confirmed a strong binding affinity for Fe (II) and Ni (II). The results suggest that potassium chloride and sodium carbonate modification are very suitable for green algae and cyanobacteria for the efficient removal of heavy metals.

At present, the imbalance in regional development and carbon emissions are the two major challenges that China faces in terms of achieving high-quality development. This paper takes regional development differences as the starting point. First, we adopt the improved CRITIC method to measure the comprehensive development level of 30 regions in China and use K-means clustering to divide the 30 regions into five development levels. Second, the structural path analysis for environmental input–output analysis (EIOA-SPA) model is used to quantify the transfer of carbon emissions between sectors in various regions. Finally, a comprehensive analysis is performed based on the development characteristics of each region and the decomposition results of the carbon emission paths. Then, more precise carbon emission reduction strategies are proposed for the development of different regions in China. The results show that first, the development gap between regions in China has improved, and the development of the central and western regions has achieved remarkable results. However, differences between the north and the south and the gap between coastal and inland regions still exist. Second, the direct carbon emissions of regions with different levels of development are mainly derived from high energy-consuming sectors, especially the production and supply of electricity and heat sector. Third, there are certain differences in the indirect carbon emission pathways of regions with different development levels. The transportation, storage, and postal sector in high developed regions have obvious driving effects on carbon emissions. The building sector plays a prominent role in driving carbon emissions in high developed regions and medium–high developed regions. The building sector, nonmetallic mineral products sector, metal smelting sector, and rolled processed product sector in medium developed regions and medium–low developed regions have relatively high carbon emission-stimulating effects. Therefore, it is necessary to adopt differentiated emission reduction strategies for regions with different development levels in China to achieve adequate carbon emission reductions. This effort would further promote the construction of China’s ecological civilization.

This work is a 7-year study of monsoonal rainwater chemistry (n = 302), over mid-Brahmaputra plain during 2012 to 2018. The samples were analyzed for major chemical parameters viz. pH, electrical conductivity (EC), and ions (SO₄²⁻, NO₃⁻, Br⁻, Cl⁻, F⁻, Mg²⁺, Ca²⁺, K⁺, NH₄⁺, Na⁺, and Li⁺) to assess the chemistry. The mean pH of rainwater varied among the years, which was maximum in 2018 (6.18 ± 0.72) and minimum in the year 2014 (5.39 ± 0.54), and the variations were significant at p < 0.0001. Ridgeline plots were drawn to visualize interannual variations, which revealed that Ca²⁺ was the dominant cation in the early years, whereas NH₄⁺ prevailed in the latter years. Mann–Kendall analysis and Sen’s slope statistical tests were employed, and it was found that all the ions showed positive S values indicating increasing trends. Enrichment factors (EF) of K⁺, SO₄²⁻, and NO₃⁻ were found to be high with respect to both soil and seawater suggesting the influence of emissions from fossil fuel and biomass burning in the chemistry of rainwater. Principal component analysis (PCA) was applied to identify the sources of rain constituents, and five factors were obtained explaining crustal dust, biomass burning, fossil fuel combustion, agricultural emissions, and coal burning as possible sources. Airmass back trajectory clusters and Potential Source Contribution Function (PSCF) were computed by application of HYbrid Single-Particle Lagrangian Integrated Trajectory model to appreciate the terrestrial influence on the chemistry. The results indicated inputs from both local and regional dust and anthropogenic constituents that influenced the monsoonal rainwater chemistry over Brahmaputra Valley.

A novel model is presented for reliable estimation of the stability constants of the thiosemicarbazone ligands with different types of toxic heavy metal ions (log β₁₁) in an aqueous solution, which has wide usage in environmental safety and ecotoxicology applications. The biggest reported data of log β₁₁ for 120 metalthiosemicarbazone complexes are used for deriving and testing the novel model. In contrast to available methods where they need the two-dimensional (2D) and three-dimensional (3D) complex molecular descriptors as well as expert users and computer codes, the novel correlation uses four additive and two non-additive structural parameters of thiosemicarbazone ligands. The calculated results of the novel correlation are compared with the outputs of the genetic algorithm with multivariate linear regression method (GA-MLR) as one of the best existing methods, which requires seven complex descriptors. The estimated results for 78 of training as well as 42 of two different test sets were established by external and internal validations. The values of statistical parameters comprising average deviation, average absolute deviation, average absolute relative deviation, absolute maximum deviation, and the coefficient of determination for 73 data of training set of New model/GA-MLR are 0.04/ − 0.25, 1.06/1.31, 14.4/18.7, 3.18/7.92, and 0.830/0.652, respectively. Thus, the predicted results of the new model are worthy as compared to the complex GA-MLR model. Moreover, assessments of various statistical parameters confirm that the new model provides great reliability, goodness-of-fit, accuracy, and precision.

Nationally determined contributions were at the core of the Paris Agreement for the global response to climate change. However, with the geographical separation of production and consumption caused by international trade, traditional trade statistics can no longer accurately reflect the flows of economic value and carbon emissions between countries, which will affect the participation and implementation of global climate policies. Based on a multi-regional input–output model, we measured the embodied carbon flows of bilateral trade between developed countries represented by Germany and the US, discussed the decoupling relationship between embodied carbon and export-led growth, and finally used structural decomposition analysis (SDA) to show how the driving factors affect embodied carbon flow in German-US trade. We found that from 2000 to 2014, embodied carbon in German-US trade showed an overall downward trend. While Germany maintained a trade surplus with the US, it also maintained an embodied carbon surplus. In addition, embodied carbon and value added in Germany’s exports to the US were mostly strongly decoupled, while in US exports to Germany were mostly weakly decoupled, and the two-way decoupling had been weakened in the later stage. The results of SDA showed that changes in carbon intensity clearly inhibited bilateral carbon flows, while trade scale effects promoted it. This study provided an opportunity to use trade to achieve carbon reduction and increased the possibility of providing a convenient and feasible market mechanism for emission reduction through international partnerships.

A large number of livestock and poultry breeding were distributed in the suburbs, brought a strong environmental pressure to the cities. The issue of whether livestock and poultry breeding could be carried out in the suburbs was a key controversy in the present. To address this question, this study constructed an index system of suitability evaluation of spatial layout of intensive pig farms, calculated the average surface temperature from June to September, and obtained potential intensive pig farms in Nanyu Town. Combing above results and area index results of cultivated land spatial matched with intensive pig farm, spatial relation between cultivated land and potential intensive pig farm was built, the optimum potential intensive pig farm in Nanyu Town was determined, and its carrying capacity was calculated. Results showed that livestock and poultry breeding could be carried out in the suburbs. A total of 3403 and 3253 pieces of cultivated lands occupying 52.01% and 49.67% of the total cultivated lands had a spatial relation between potential intensive pig farms taking N and P as indices, respectively. Moreover, 14 and 15 potential intensive pig farms taking N and P as indices, respectively, in Nanyu Town were determined as optimum potential intensive pig farms. Results also indicated that most of the optimum potential intensive pig farms were suitable for constructing small- and medium-sized pig farms. Results would provide scientific basis for the planning of spatial arrangement of livestock and poultry breeding and the suburb environmental pollution control.

Information on biomass carbon storage in bamboo plantations/groves at local or regional landscapes is crucial to understand its potential in carbon stock management and climate change mitigation. The present work aims to study soil properties, litter dynamics and biomass carbon storage for the three common bamboo species from the Terai region of Indian Eastern Himalayas. Bambusa nutans, Dendrocalamus giganteus and Melocanna baccifera groves were selected for the present study. The soil pH, moisture and electrical conductivity under different bamboo groves of three species varied significantly, but moisture and electrical conductivity responded inconsistently with increasing soil depth. Similarly, the amount of soil available primary nutrients also varied significantly, where soils of M. baccifera grove were quantified with highest amount of these nutrients at all depths. M. baccifera grove produced the highest litter, although the difference with the other two groves was non-significant. The amount of oxidizable soil organic carbon quantified varied significantly among the bamboo groves, with the highest SOC content under the M. baccifera grove. The decomposition rate gradually increased with time, and within 9 months, the entire litter got decomposed. The annual return of nutrients was in the order N > K > P. The total biomass of D. giganteus, B. nutans and M. baccifera was estimated at 270.97, 127.21 and 16.31 Mg ha⁻¹, respectively. Based on the higher R² and adj R², and lower AIC and HQC, Model 1 was more appropriate for B. nutans and D. giganteus, whereas Model 2 was suitable for M. baccifera. The ecosystem carbon stock of D. giganteus was significantly (163.28 Mg ha⁻¹) higher than the other two species because of its significantly higher biomass carbon accumulation. This amount of biomass carbon storage and ecosystem carbon stock is comparable with agroforestry and forest ecosystems in the study region or elsewhere. The present study suggests these bamboos can be a feasible option for carbon farming and carbon trading, climate change adaptation and mitigation, apart from its contribution in social and economic contributions to the region’s rural life. Therefore, value addition and nationalizing of bamboo are recommended to improve rural folks’ livelihood. Encouraging value-added bamboo products can be negative feedback to climate change because of their durability and thus permanency of carbon stored in it.

Humic substances (HSs) can ameliorate soil pollution by mediating electron transfer between microorganisms and contaminants. This capability depends on the redox-active functional structure and electron transfer capacity (ETC) of HS. This study mainly aimed to analyze the effects of different ventilation quantities on the ETC and spectral characteristics of HS (including humic acids (HAs) and fulvic acids (FAs)) during sludge composting. HS was extracted from compost with different ventilation quantities (0.1, 0.2, and 0.3 L kg⁻¹ dry matter min⁻¹, denoted as VQ1, VQ2, and VQ3, respectively). The ETC of HS was measured by electrochemical method. Excitation–emission matrix (EEM) spectroscopy, ultraviolet and visible (UV–Vis) spectrophotometry, and Fourier transform infrared (FT-IR) spectroscopy were conducted to understand the evolution of HS composition during composting. Results indicated that the ETC of HA and FA increased during composting, and VQ2 had stronger ETC and electron recycling rate than VQ1 and VQ3 at the end of composting. UV–Vis analysis revealed that the humification degree, aromatization degree, and molecular weight of HA and FA increased during composting, while the content of lignin decreased. EEM-PARAFAC results suggested that VQ2 accelerated the degradation of protein-like substances. FT-IR revealed a decrease trend in polysaccharide and aliphatic, and the carboxyl content increased in VQ2 and VQ3 while decreased in VQ1. Correlation analysis was used to study the relationship between HS components and ETC. The results advance our further understanding of the pollution remediation mechanism of HS.

This study aims to analyze the asymmetric long-run relationship between economic growth (EG), foreign direct investment (FDI), and carbon emissions (CO₂) within the context of the environmental Kuznets curve (EKC) and the pollution haven hypothesis (PHH) in China. Employing the quarterly data from 1982Q1 to 2018Q4, we have used novel techniques to meet the stated objectives of our study, named quantile ARDL and quantile Granger causality. The study provides novel outcomes using the advanced quantile ARDL and quantile Granger causality tests. The significant implication of this method is that it provides locational asymmetry. We find strong evidence of the EKC and PHH for China based on the empirical results of linear and nonlinear ARDL models. Similarly, findings of quantile Granger causality validate the bidirectional relationship among all variables in upper and lower quantiles. Moreover, the results of the Wald test confirm the asymmetric long-run relationship between FDI and carbon emissions (CO₂). Thus, legal measures must be enhanced, accepted, rigorously imposed, and monitored in all provinces to assure a further reduction in carbon emissions. This study will be conducive for the policymakers to combat environmental contamination concerning economic growth and FDI inflow in China.